1. Field of the Invention
The present invention relates to Poly(2-Octadecyl Butanedioic acid) and the salts and esters thereof, and more particularly pertains to the uses of Poly(2-Octadecyl Butanedioate) and Poly(2-Octadecyl Butanedioic Acid) as polycarbonate organic polymers. This application pertains to the uses of the herein described compound in ways heretofore not disclosed or taught.
2. Description of the Prior Art
Organic polymers (plastics) are amorphous solids that characteristically become brittle on cooling and soft on heating. The temperature at which this structural transition takes place is known as the glass transition temperature. More specifically, the IUPAC Compendium of Chemical Terminology defines the glass transition temperature as a pseudo second order phase transition in which a super-cooled melt yields a glassy structure with properties similar to those of crystalline materials upon cooling (The IUPAC Compendium of Chemical Terminology, 66, 83 (1997)). Above this temperature, these materials become soft and capable of deformation without fracture due to the weakening of the secondary, non-covalent bonds between the polymer chains. This characteristic enhances the usefulness of a subset of plastic materials known as thermoplastics. Those schooled in the art know that the transition temperature for a polymer can be influenced by the addition of plasticizers, other polymeric substances, the cooling-ratio, and its molecular weight distribution. The mean glass transition temperature for polycarbonate is reported to be 145° C. (Engineered Materials Handbook-Desk edition (1995) ASM International, ISBN 0871702835. p. 369).
Many polymers, including polycarbonates, can be used for several molding processes including, injection, extrusion, and extrusion/injection blow molding. In injection molding, these thermoplastics are heated and then pressed into a mold to form different shape plastics. In extrusion molding, the polymer is melted into a liquid and forced through a die forming a long continuous piece of plastic with the shape of the die. When the extruded material cools, it forms a solid with the desired shape. Blow molding is a process by which hollow plastic parts are formed either by injection or extrusion. Those schooled in the art know that the optimum polymer melt temperature, die and mold temperature, and annealing conditions must be empirically determined for each plastic material and mold/die configuration. Polycarbonate resins are tough thermoplastics with very high visual clarity and exceptionally high levels of impact strength and ductility. Polycarbonate resins, or “Polycarbonates” also possess inherent fire resistance, relatively good resistance to UV light, good resistance to aqueous solutions of organic and inorganic acids and good resistance salts and oxidizing agents, but offer limited resistance to organic solvents. Typical properties of polycarbonates include exceptional machine-ability, low water absorption, good impact resistance, non-toxic formulations, good thermal properties, superior dimensional stability, heat resistance, and transparency with thicknesses up to 2″.
Currently, major markets for polycarbonate resins include the electrical/electronic sectors, such as computer and business equipment and optical disks, sheet and glazing products, and the automotive industry. Other products include safety helmets, safety shields, housing components, household appliances, sporting goods, and aircraft and missile components. Specific product applications include doors, equipment enclosures, greenhouses, high voltage switches, high temperature windows, instrument gauge covers, automotive instrument panels, light bezels, pumps and valves, connectors, gears, internal mechanical parts, relays, rollers, lenses, sight glasses, light shields, machine guards, patio roofs, photo lens covers, replacement for metal components of safety equipment, guards, helmets, shields, signs, solar rods, thermal insulation, thermometer housings, and window glazing. Polycarbonates have also received approval from the U.S. Food and Drug Administration for use in medical instruments, medical implants, and tubing.
Polycarbonate, while broadly used, is limited in specific instances. As previously mentioned, polycarbonate typically shows good resistance (at room temperature) to water, dilute organic and inorganic acids, neutral and acid salts, and aliphatic and cyclic hydrocarbons. It does not resist attacks from alkalines, amines, ketones, esters, and aromatic hydrocarbons.
Several US retailers have begun to remove polycarbonate food and beverage containers from their shelves due to concerns that small amounts of bisphenol-A (BPA), a component of polycarbonates, can be released from the polymer over time. The US government's National Toxicology Program has indicated that there is limited evidence that low doses of BPA can cause health problems and reproductive defects in humans.
Polycarbonates can generally be classified into two major categories: aromatic and aliphatic. Aromatic polycarbonates are prepared by the reaction of an aromatic diol with phosgene gas (COCl2). (See FIG. 3; Howdeshell, K. L., et. al. “Bisphenol A is Released from Used Polycarbonate Animal Cages into Water at Room Temperature.” Environ. Health Perspect. 111(9):1180-1187 (2003). Bisphenol-A is typically used as the aromatic diol and has been the subject of health concerns associated with its release from the polymer. It is currently not known if the source of bisphenol-A is through leaching of the monomer due to incomplete polymerization or hydrolysis of the polymer induced by heating and/or contact with acidic or basic materials.
Aliphatic polycarbonates are frequently used as bioresorbable materials for biomedical applications, such as medical implants and drug delivery carriers (see; Raigorodskii, I. M., et. al. Soedin., Ser. A. 37(3):445 (1995); Acemoglu, M. PCT Int. Appl., WO 9320126 (1993); Katz, A. R., et. al., Surg. Gynecol. Obstet. 161:312 (1985); Rodeheaver G. T., et. al., Am. J. Surg. 154:544 (1987) Kawaguchi, T., et. al., Chem. Pharm. Bull. 31, 1400:4157 (1983); Kojima, T., et. al., Chem. Pharm. Bull. 32:2795 (1984). These materials generally show good biocompatibility, low toxicity, and biodegradability (Zhu, K. J., et. al., Macromolecules. 24:1736 (1991)). Poly alkylene carbonates have been synthesized by the reaction of aliphatic diols with phosgene (Schnell, H. Chemistry and Physics of Polycarbonates, Wiley, N.Y., 1964, p 9), the copolymerization of epoxides with carbon dioxide in the presence of organometallic catalysts (Inoue, S., Koinuma, H., Tsuruta, T. Makromol. Chem. 120:210 (1969)), the ring-opening polymerization of cyclic carbonate monomers (Hocker, H. Macromol. Rep., A31 (Suppls. 6&7), 685 (1994)), carbonate interchange reactions between aliphatic diols and dialkyl carbonates (Pokharkar, V., Sivaram, S. Polymer, 36:4851 (1995)), and the direct condensation of diols with CO2 or alkali metal carbonates (see; Soga, K. et. al., Makromol. Chem. 178:2747 (1977); Rokicki, G., et. al., J. Polym. Sci., Polym. Chem. Ed., 20:967 (1982); Rokicki, G., et. al., Polym. J. 14:839 (1982); Chen, X., et. al., Macromolecules, 30:3470-3476 (1997)).